282 research outputs found

    Innovative Fuel Design to Improve Proliferation Management

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    This research uses an existing innovative fuel design (IFD) that has intrinsic safety features and enhanced economics over the current uranium dioxide (UO2) light water fuel design and evaluates promising methods to improve the waste management and proliferation resistance of the IFD by doping the fresh fuel with select actinides.The most robust approach for proliferation resistance is to denature these materials by adding a uranium or plutonium isotope that hampers the usability of the materials in weapons. The proposed modifications to the IFD use this approach through elevated fractions of 238Pu. 238Pu generates large quantities of heat and neutrons through its radioactive decay and is estimated to make plutonium potentially “proliferation-proof. The IFD this work uses as a foundation is an advanced metallic fuel designed for use in current light water reactors. Due to the high fission density of metallic fuel and the proposed uranium enrichments, the plutonium produced by irradiating this fuel has promising isotopic content for proliferation resistance. This proliferation resistance will be further increased by adding 237Np and/or 241Am to the initial fresh fuel composition that will result in increased 238Pu content. Adding these actinides into the fresh fuel at 0.2 wt.%, the amount of 238Pu produced in the used fuel can be used for proliferation resistance. Increasing the actinide wt.% can potentially produce proliferation-proof used fuel. Also, by utilizing neptunium and americium in fresh fuel, many of the challenges with permanent geological disposal of used fuel can be mitigated

    Specialist Outreach to Isolated and Disadvantaged Communities: A Population-Based Study

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    Background Visiting-specialist clinics (specialist outreach) have the potential to overcome some of the substantial access barriers faced by disadvantaged rural, remote, and Indigenous communities, but the effectiveness of outreach clinics has not been assessed outside urban and non-disadvantaged settings. We aimed to assess the effects of outreach clinics on access, referral patterns, and care outcomes in remote communities in Australia. Methods We undertook a population-based observational study of regular surgical, ophthalmological, gynaecological, and ear, nose, and throat outreach visits, compared with hospital clinics alone, on access, referral practices, and outcomes for the populations of three remote Indigenous communities in northern Australia for 11 years. We assessed all new non-emergency potential specialist surgical cases who presented initially between Jan 1, 1990, and Jan 1, 2001. The effects of outreach clinics on the proportion of patients referred, the time from referral to initial specialist consultation, and the rates of community-based and hospital-based procedures were analysed using logic regression and Cox proportional hazard models. Findings 2339 new surgical problems presented in 2368 people between 1990 and 2001. Outreach improved the rate of referral completion (adjusted hazard ratio 1.41, 95% CI 1.07-1.86) and the risk of timely completion according to the urgency of referral (adjusted relative risk 1.30, 1.05-1.53). Outreach had no significant effect on initiation of elective referrals, but there were 156 opportunistic presentations on outreach clinic days. Specialist investigations and procedures in community clinics removed the need for many patients to travel to hospital, and outreach consultations were associated with a reduced rate of procedures that needed hospital admission (adjusted hazard ratio 0.67, 0.43-.03). Interpretation Specialist outreach visits to remote disadvantaged Indigenous communities in Australia improve access to specialist consultations and procedures without increasing elective referrals or demands for hospital inpatient services

    Selective Disparity of Ordinary Chondritic Precursors in Micrometeorite Flux

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    All known extraterrestrial dust (micrometeoroids) entering the Earth's atmosphere is anticipated to have a significant contribution from ordinary chondritic precursors, as seen in meteorites, but this is an apparent contradiction that needs to be addressed. Ordinary chondrites represent a minor contribution to the overall meteor influx compared to carbonaceous chondrites, which are largely dominated by CI and/or CM chondrites. However, the near-Earth asteroid population presents a scenario with sufficient scope for generation of dust-sized debris from ordinary chondritic sources. The bulk chemical composition of 3255 micrometeorites (MMs) collected from Antarctica and deep-sea sediments has shown Mg/Si largely dominated by carbonaceous chondrites, and less than 10% having ordinary chondritic precursors. The chemical ablation model is combined with different initial chondritic compositions (CI, CV, L, LL, H), and the results clearly indicate that high-density (≥2.8 g cm⁻³) precursors, such as CV and ordinary chondrites in the size range 100–700 μm and zenith angle 0°–70°, ablate at much faster rates and lose their identity even before reaching the Earth's surface and hence are under-represented in our collections. Moreover, their ability to survive as MMs remains grim for high-velocity micrometeoroids (>16 km s⁻¹). The elemental ratio for CV and ordinary chondrites are also similar to each other irrespective of the difference in the initial chemical composition. In conclusion, MMs belonging to ordinary chondritic precursors' concentrations may not be insignificant in thermosphere, as they are found on Earth's surface

    Multimorbidity prevalence and patterns across socioeconomic determinants: a cross-sectional survey

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    <p>Abstract</p> <p>Background</p> <p>Studies on the prevalence of multimorbidity, defined as having two or more chronic conditions, have predominantly focused on the elderly. We estimated the prevalence and specific patterns of multimorbidity across different adult age groups. Furthermore, we examined the associations of multimorbidity with socio-demographic factors.</p> <p>Methods</p> <p>Using data from the Health Quality Council of Alberta (HQCA) 2010 Patient Experience Survey, the prevalence of self reported multimorbidity was assessed by telephone interview among a sample of 5010 adults (18 years and over) from the general population. Logistic regression analyses were performed to determine the association between a range of socio-demographic factors and multimorbidity.</p> <p>Results</p> <p>The overall age- and sex-standardized prevalence of multimorbidity was 19.0% in the surveyed general population. Of those with multimorbidity, 70.2% were aged less than 65 years. The most common pairing of chronic conditions was chronic pain and arthritis. Age, sex, income and family structure were independently associated with multimorbidity.</p> <p>Conclusions</p> <p>Multimorbidity is a common occurrence in the general adult population, and is not limited to the elderly. Future prevention programs and practice guidelines should take into account the common patterns of multimorbidity.</p

    Four aspects of self-image close to death at home

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    Living close to death means an inevitable confrontation with one's own existential limitation. In this article, we argue that everyday life close to death embodies an identity work in progress. We used a narrative approach and a holistic-content reading to analyze 12 interviews conducted with three persons close to death. By illuminating the unique stories and identifying patterns among the participants’ narratives, we found four themes exemplifying important aspects of the identity work related to everyday life close to death. Two of the themes, named “Inside and outside of me” and “Searching for togetherness,” represented the core of the self-image and were framed by the other themes, “My place in space” and “My death and my time.” Our findings elucidate the way the individual stories moved between the past, the present, and the future. This study challenges the idea that everyday life close to impending death primarily means limitations. The findings show that the search for meaning, new knowledge, and community can form a part of a conscious and ongoing identity work close to death

    MRE11 and RAD50, but not NBS1, are essential for gene targeting in the moss Physcomitrella patens

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    The moss Physcomitrella patens is unique among plant models for the high frequency with which targeted transgene insertion occurs via homologous recombination. Transgene integration is believed to utilize existing machinery for the detection and repair of DNA double-strand breaks (DSBs). We undertook targeted knockout of the Physcomitrella genes encoding components of the principal sensor of DNA DSBs, the MRN complex. Loss of function of PpMRE11 or PpRAD50 strongly and specifically inhibited gene targeting, whilst rates of untargeted transgene integration were relatively unaffected. In contrast, disruption of the PpNBS1 gene retained the wild-type capacity to integrate transforming DNA efficiently at homologous loci. Analysis of the kinetics of DNA-DSB repair in wild-type and mutant plants by single-nucleus agarose gel electrophoresis revealed that bleomycin-induced fragmentation of genomic DNA was repaired at approximately equal rates in each genotype, although both the Ppmre11 and Pprad50 mutants exhibited severely restricted growth and development and enhanced sensitivity to UV-B and bleomycin-induced DNA damage, compared with wild-type and Ppnbs1 plants. This implies that while extensive DNA repair can occur in the absence of a functional MRN complex; this is unsupervised in nature and results in the accumulation of deleterious mutations incompatible with normal growth and development

    Preventive evidence into practice (PEP) study: implementation of guidelines to prevent primary vascular disease in general practice protocol for a cluster randomised controlled trial

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    There are significant gaps in the implementation and uptake of evidence-based guideline recommendations for cardiovascular disease (CVD) and diabetes in Australian general practice. This study protocol describes the methodology for a cluster randomised trial to evaluate the effectiveness of a model that aims to improve the implementation of these guidelines in Australian general practice developed by a collaboration between researchers, non-government organisations, and the profession.This study is funded by an Australian National Health and Medical Research Council (NHMRC) Partnership grant (ID 568978) together with the Australian National Heart Foundation, Royal Australian College of General Practitioners, and the BUPA Foundation. MH is supported by a NHMRC Senior Principle Research Fellowship

    How group identification helps to overcome the dilemma of collective action

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    According to the basic assumption underlying this article, people are more likely to participate in protest the more they feel that a group they identify with is treated unjustly. Depersonalization and the politicization of group identification are discussed as two processes that mediate the relationship between group identification and protest participation. Empirical evidence from three studies is discussed. In a study among people older than 55, participation in unions for the elderly appears to be correlated strongly with identification with the elderly. In a study of participation in peaceful protest among South African citizens, indicators of identification appeared to be correlated with protest participation, and finally, Dutch farmers were more likely to participate in farmers' protest the more they identified with other farmers. Results from the latter, longitudinal study suggest a recursive relationship between identity and protest participation: Group identification fosters protest participation and protest participation reinforces group identification
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